Comminution machines are used to reduce waste materials such as trees, brush, stumps, pallets, root balls, railroad ties, peat moss, paper, wet organic materials, fibrous materials such as empty fruit bunches and the like. Two common types of comminution machines include grinders and chippers. Grinders are typically configured to reduce material through blunt force impactions. Thus, the reduced material product generated by grinders generally has a ground, flattened texture with relatively high fines content. This type of reduced material is typically used as mulch. In contrast to the blunt force action used by grinders, chippers reduce material through a chipping action. The reduced product generated by chippers preferably has a relatively small percentage of fines. This type of chipped reduced product can readily be used as fuel for a burner since the material is more flowable than ground reduced material and can easily be handled by the material processing equipment used to feed fuel to a burner.
Grinders typically include reducing hammers on which replaceable grinding cutters (i.e., grinding tips or grinding elements) are mounted. Grinding cutters generally have relatively blunt ends suitable for reducing material through blunt force impactions. Screens are often used to control the size of the reduced material output from grinders. In contrast to the grinding cutters used on grinders, chippers typically include relatively sharp chipping knives configured to reduce material through a cutting/slicing action as opposed to a grinding action.